Chesapeake (CHK -5.4%) opens trading as the S&P's biggest loser after a report of alleged...

Chesapeake (CHK-5.4%) opens trading as the S&P's biggest loser after a report of alleged bid rigging by CHK and Encana (ECA-3.2%), plus a story that J.P. Morgan declined to do loan business with CHK for more than 10 years because of credit quality, while Goldman Sachs took the business.